Response of soybean [Glycine max L. (Merrill)] to starter nitrogen in Western Ethiopia

Abstract

ABSTRACT Soil acidity and poor soil fertility are major constraints that limit soybean productivity in Western Ethiopia. Thus, this study was conducted to identify the effect of starter nitrogen on soybean growth and yield, both under inoculated and uninoculated conditions, and to identify economically feasible treatments that can maximize the productivity of soybean. Factorial combinations of two levels of inoculants (un-inoculated and inoculated), two soybean varieties (Boshe and Dhidhessa) and four levels of nitrogen (0, 20, 40 and 60 kg N ha−1) were laid out in split-plot design with three replications. The results showed that some growth and yield contributing traits of soybeans were significantly affected by the main effects of inoculant varieties and nitrogen rates. In contrary, nodule and pod numbers per plant and grain yield were significantly influenced by the interaction effect of inoculants, varieties and nitrogen rates. The highest grain yield was recorded at 20 and 40 kg ha−1. The highest net benefit (622.5 USD ha−1) and marginal rate of return (455.8%) were recorded from the application of nitrogen at 20 kg N ha −1. Thus, it can be concluded that application of starter nitrogen at 20 kg N ha−1 is recommended for soybean production in Western Ethiopia.